Endothelial Cell Proliferation Research Articles

Inhibitory Effect of Phenolic Compounds on Vascular Endothelial Growth Factor-Induced Retinal Endothelial Permeability and Angiogenesis.

Age-related macular degeneration (AMD), often triggered by endothelial barrier disruption through vascular endothelial growth factor (VEGF), is a leading cause of blindness. This study investigated the inhibitory effects of phenolic compounds on VEGF-induced endothelial cell proliferation, migration, angiogenesis, and permeability using human retinal microvascular endothelial cells (hRECs). Thirty-seven polyphenolic compounds were selected from various databases based on their antioxidant properties, abundance in food, and solubility. These compounds significantly reduced migration, tube formation, and endothelial permeability in VEGF-stimulated hRECs. Notably, formononetin, eriodictyol, biochanin A, and p-coumaric acid were more effective in suppressing VEGF-induced angiogenesis and endothelial permeability than lutein. Molecular docking simulations revealed that formononetin, eriodictyol, and biochanin A had relatively lower binding energies with VEGF receptor 2 (VEGFR2) than lutein and sorafenib. These findings highlight the potential of phenolic compounds to be used as VEGFR2 inhibitors and an alternative strategy for preventing AMD.

Cabozantinib prevents the progression of metabolic dysfunction-associated steatohepatitis by inhibiting the activation of hepatic stellate cell and macrophage and attenuating angiogenic activity

Cabozantinib, a multiple tyrosine kinase inhibitor targeting AXL, vascular endothelial growth factor receptor (VEGFR), and MET, is used clinically to treat certain cancers, including hepatocellular carcinoma. This study aimed to assess the impact of cabozantinib on liver fibrosis and hepatocarcinogenesis in a rat model of metabolic dysfunction-associated steatohepatitis (MASH). MASH-based liver fibrosis and hepatocarcinogenesis were induced in rats by feeding them a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) for eight and 16 weeks, respectively. Cabozantinib (1 or 2 mg/kg, daily) was administered concurrently with the diet in the fibrosis model and after eight weeks in the carcinogenesis model. Treatment with cabozantinib significantly attenuated hepatic inflammation and fibrosis without affecting hepatocyte steatosis and ballooning in CDAHFD-fed rats. Cabozantinib-treated rats exhibited a marked reduction in α-smooth muscle actin+ activated hepatic stellate cell (HSC) expansion, CD68+ macrophage infiltration, and CD34+ pathological angiogenesis, along with reduced hepatic AXL, VEGF, and VEGFR2 expression. Consistently, cabozantinib downregulated the hepatic expression of profibrogenic markers (Acta2, Col1a1, Tgfb1), inflammatory cytokines (Tnfa, Il1b, Il6), and proangiogenic markers (Vegfa, Vwf, Ang2). In a cell-based assay of human activated HSCs, cabozantinib inhibited Akt activation induced by GAS6, a ligand of AXL, leading to reduced cell proliferation and profibrogenic activity. Cabozantinib also suppressed lipopolysaccharide-induced proinflammatory responses in human macrophages, VEGFA-induced collagen expression and proliferation in activated HSCs, and VEGFA-stimulated proliferation in vascular endothelial cells. Meanwhile, administration of cabozantinib did not affect Ki67+ hepatocyte proliferation or serum albumin levels, indicating no negative impact on regenerative capacity. Treatment with cabozantinib also reduced the placental glutathione transferase+ preneoplastic lesions in CDAHFD-fed rats. In conclusion, cabozantinib shows promise as a novel option for preventing MASH progression.

Resected intramuscular hemangioma in the chest wall: a case report

BackgroundIntramuscular hemangioma is an uncommon benign tumor found mainly in the limbs of adolescents and young adults. The local recurrence rate is high, ranging from 30 to 50%, necessitating wide local excision of intercostal intramuscular hemangiomas. However, preoperative diagnosis of intramuscular hemangiomas is challenging. Herein, we report a rare case of an intramuscular hemangioma arising from the chest wall.Case presentationA healthy 29-year-old asymptomatic man was referred to our hospital after an abnormal shadow was observed on his chest radiography. Computed tomography and magnetic resonance imaging revealed a 30-mm-sized mass in the right second intercostal space. Neoplastic lesions, such as schwannomas or solitary fibrous tumors, were included in the preoperative differential diagnosis. Tumor resection was performed using video-assisted thoracoscopic surgery. The tumor, which had a smooth surface covered with parietal pleura, was dissected from the external intercostal muscle and costal bone. Postoperative histopathological examination revealed proliferation of spindle-shaped endothelial cells arranged in a capillary vascular structure accompanied by entrapped smooth muscle fibers, adipose tissue, and muscle vessels. The final diagnosis was an intramuscular hemangioma with negative surgical margins. There was no evidence of recurrence during the 1-year postoperative follow-up period.ConclusionIntramuscular hemangiomas should be considered in the differential diagnosis of chest wall tumors, particularly in young people, owing to their potential for recurrence. Moreover, postoperative follow-up may be necessary for resected intramuscular intercostal hemangiomas.

Metabolomics integrated with network pharmacology of blood-entry constituents reveals the bioactive component of Xuefu Zhuyu decoction and its angiogenic effects in treating traumatic brain injury

BackgroundXuefu Zhuyu decoction (XFZYD) has been extensively utilized to treat traumatic brain injury (TBI). However, the bioactive compounds and the underlying mechanisms have not yet been elucidated.ObjectivesThis study aimed to investigate the bioactive constituents of XFYZD that are absorbed in the blood and the mechanisms in treating TBI.MethodsThe study presents an integrated strategy in three steps to investigate the material basis and pharmacological mechanisms of XFZYD. The first step involves: (1) performing metabolomics analysis of XFZYD to obtain the main functions and targets; (2) screening the blood-entry ingredients and targets of XFZYD from databases; (3) obtaining the potential components targeting the key functions by integrated analysis of metabolomics and network pharmacology. The second step involves screening pharmacological effects with active ingredients in vitro. In the third step, the effects of the top active compound were validated in vivo, and the mechanisms were explored by protein antagonist experiments.ResultsMetabolomics analysis revealed that XFZYD treated TBI mice mainly through affecting the functions of blood vessels. We screened 62 blood-entry ingredients of XFZYD by network pharmacology. Then, we focused on 39 blood-entry ingredients related to vascular genes enriched by XFZYD-responsive metabolites. Performing the natural products library, we verified that hydroxysafflor yellow A (HSYA), vanillin, ligustilide, paeoniflorin, and other substances promoted endothelial cell proliferation significantly compared to the control group. Among them, the efficacy of HSYA was superior. Further animal studies demonstrated that HSYA treatment alleviated neurological dysfunction in TBI mice by mNSS and foot fault test, and decreased neuronal damage by HE, nissl, and TUNEL staining. HSYA increased the density of cerebral microvessels, raised the expression of angiogenesis marker proteins VEGFA and CD34, and activated the PI3K/Akt/mTOR signaling pathway significantly. The angiogenic effects disappeared after the intervention of PI3K antagonist LY294002.ConclusionBy applying a novel strategy of integrating network pharmacology of constituents absorbed in blood with metabolomics, the research screened HSYA as one of the top bioactive constituents of XFZYD, which stimulates angiogenesis by activating the PI3K/Akt/mTOR signaling pathway after TBI.

Highly concentrated collagen/chondroitin sulfate scaffold with platelet-rich plasma promotes bone-exposed wound healing in porcine.

In the case of wounds with exposed bone, it is essential to provide not only scaffolds with sufficient mechanical strength for protection, but also environments that are conducive to the regeneration of tissues and blood vessels. Despite the excellent biocompatibility and biodegradability of collagen and chondroitin sulfate, they display poor mechanical strength and rapid degradation rates. In contrast to previous methodologies that augmented the mechanical properties of biomaterials through the incorporation of additional substances, this investigation exclusively enhanced the mechanical strength of collagen/chondroitin sulfate scaffolds by modulating collagen concentrations. Furthermore, platelet-rich plasma (PRP) was employed to establish optimal conditions for vascular and tissue regeneration at the wound site. High-concentration collagen/chondroitin sulfate (H C-S) scaffolds were synthesized using high-speed centrifugation and combined with PRP, and their effects on endothelial cell proliferation were assessed. A porcine model of bone-exposed wounds was developed to investigate the healing effects and mechanisms. The experimental results indicated that scaffolds with increased collagen concentration significantly enhanced both tensile and compressive moduli. The combination of H C-S scaffolds with PRP markedly promoted endothelial cell proliferation. In vivo experiments demonstrated that this combination significantly accelerated the healing of porcine bone-exposed wounds and promoted vascular regeneration. This represents a promising strategy for promoting tissue regeneration that is worthy of further exploration and clinical application.

14K prolactin derived 14-mer antiangiogenic peptide targets bradykinin-/nitric oxide-cGMP-dependent angiogenesis.

Over the past few decades, VEGF-targeted antiangiogenic therapy for cancers has gained increasing attention. Nevertheless, there are still several limitations such as the potential resistance mechanisms arising in cancer cells against these therapies and their potential adverse effects. These limitations highlight the need for novel anti-angiogenesis molecules and better understanding of the mechanisms of tumor angiogenesis. In the present study, we investigated the antiangiogenic properties of a novel 14-mer antiangiogenic peptide (14-MAP) derived from N-terminal 14 kDa buffalo prolactin and characterized its mode of action. 14-MAP at the picomolar concentration inhibited VEGF- and bradykinin (an autacoid peptide expressed in vascular tissues in pathophysiology, BK)-stimulated endothelial nitric oxide (eNO) production, cell migration, and proliferation in endothelial cells and vessel development in the chick embryo. Although this peptide inhibited both VEGF- and BK-dependent angiogenic processes, its action was more pronounced in the latter. Moreover, the interference of 14-MAP with the eNO synthase (eNOS)-cyclic GMP pathway was also identified. A combination of a low dose of Avastin, a widely used drug targeting VEGF-dependent angiogenesis, and 14-MAP significantly reduced tumor size in an in vivo model of human colon cancer. Taken together, our results suggest that 14-MAP, a BK- and eNOS-dependent antiangiogenic peptide, might be useful for overcoming the limitation of VEGF-targeted antiangiogenic therapy in cancer patients. However, further studies will be required to further characterize its mode of action and therapeutic potential.

Glycerol‐plasticized silk fibroin vascular grafts mimic key mechanical properties of native blood vessels

AbstractCardiovascular diseases are a major global health challenge. Blood vessel disease and dysfunction are major contributors to this healthcare burden, and the development of tissue‐engineered vascular grafts (TEVGs) is required, particularly for the replacement of small‐diameter vessels. Silk fibroin (SF) is a widely used biomaterial for TEVG fabrication due to its high strength and biocompatibility. However, the stiffness of SF is much higher than that of native blood vessels (NBVs), which limits its application for vascular tissue engineering. In this study, SF was plasticized with glycerol to produce TEVGs exhibiting similar stiffness and ultimate tensile strength to those of NBVs. The electrospun SF/glycerol TEVGs exhibited mechanical properties comparable to NBVs and supported the in vitro proliferation of essential vascular cells—endothelial and smooth muscle cells. After 5 days of culture, the TEVGs exhibited an endothelial monolayer in the lumen, demonstrating their potential for functional vascular tissue regeneration. Our study demonstrates the feasibility of producing TEVGs from SF with tailored mechanical properties, paving the way for more functional and durable TEVGs for future clinical applications.

A non-genetic model of vascular shunts informs on the cellular mechanisms of formation and resolution of arteriovenous malformations

Abstract Aims Arteriovenous malformations (AVMs), a disorder characterized by direct shunts between arteries and veins, are associated with genetic mutations. However, the mechanisms leading to AV shunt formation and how shunts can be reverted are poorly understood. Methods and results Here, we report that oxygen-induced retinopathy (OIR) protocol leads to the consistent and stereotypical formation of AV shunts in non-genetically altered mice. OIR-induced AV shunts show all the canonical markers of AVMs. Genetic and pharmacological interventions demonstrated that changes in the volume of venous endothelial cells (EC)—hypertrophic venous cells—are the initiating step promoting AV shunt formation, whilst EC proliferation or migration played minor roles. Inhibition of the mTOR pathway prevents pathological increases in EC volume and significantly reduces the formation of AV shunts. Importantly, we demonstrate that ALK1 signalling cell-autonomously regulates EC volume in pro-angiogenic conditions, establishing a link with hereditary haemorrhagic telangiectasia-related AVMs. Finally, we demonstrate that a combination of EC volume control and EC migration is associated with the regression of AV shunts. Conclusion Our findings highlight that an increase in the EC volume is the key mechanism driving the initial stages of AV shunt formation, leading to asymmetric capillary diameters. Based on our results, we propose a coherent and unifying timeline leading to the fast conversion of a capillary vessel into an AV shunt. Our data advocate for further investigation into the mechanisms regulating EC volume in health and disease as a way to identify therapeutic approaches to prevent and revert AVMs.

Engineering Three-Dimensional Spheroid Culture for Enrichment of Proangiogenic miRNAs in Umbilical Cord Mesenchymal Stem Cells and Promotion of Angiogenesis.

In the field of regenerative medicine, umbilical cord-derived mesenchymal stem cells (UC-MSCs) have a plausible potential. However, traditional two-dimensional (2D) culture systems remain limited in replicating the complex in vivo microenvironment. Thus, three-dimensional (3D) cultures offer a more physiologically relevant model. This study explored the impact of 3D culture conditions on the UC-MSC secretome and its ability to promote angiogenesis, both in vitro and in vivo. In this study, using two distinct methods, we successfully cultured UC-MSCs: in a monolayer (2D-UC-MSCs) and as spheroids formed in U-shaped 96-well plates (3D-UC-MSCs). The presence and expression of proangiogenic miRNAs in the conditioned media (CM) of these cultures were investigated, and differential expression patterns were explored. Particularly, the CM of 3D-UC-MSCs revealed significantly higher levels of miR-21-5p, miR-126-5p, and miR-130a-3p compared to 2D-UC-MSCs. Moreover, the CM from 3D-UC-MSCs revealed a higher effect on endothelial cell proliferation, migration, and tube formation than did the CM from 2D-UC-MSCs, indicating their proangiogenic potential. In an in vivo Matrigel plug mouse model, 3D-UC-MSCs (cells) stimulated greater vascular formation compared to 2D-UC-MSCs (cells). 3D culture of UC-MSCs' secretome improves the promotion of angiogenesis.

“Synergistic anticoagulant and endothelial regeneration strategy” based on mussel-inspired phospholipid copolymer coating and bioactive zeolitic imidazolate frameworks-90 to maintain the patency of CoCr stent

Given the risks of poor patient compliance and bleeding associated with current dual antiplatelet therapies, it is urgent to develop the next generation of cardiovascular stents with anticoagulation and rapid endothelialization capabilities. Inspired by the prominent bioactivity and bioavailability of zeolitic imidazolate framework-90 (ZIF-90) in driving endothelial cell (EC) morphogenesis, this research proposes a “synergistic anticoagulant and endothelial regeneration strategy” depending on mussel-inspired phospholipid copolymer (MIPC) and ZIF-90. Depending on the copolymerization of the catechol with dopamine (Dopa) monomers, Dopa/MIPC coating was immobilized on the surface of CoCr via a one-pot process for resisting the initial thrombosis induced by platelets and fibrinogen. Meanwhile, ZIF-90 was loaded on the coating via coordination effect, aiming to accelerate the proliferation and migration of ECs. Compared with CoCr, the well-designed CoCr-Dopa/MIPC@ZIF-90 not only reduced fibrinogen adhesion by approximately 40 % and platelet adhesion by almost 55 %, but also promoted the proliferation and migration of ECs significantly in vitro. Furthermore, the blood flow velocity of CoCr-Dopa/MIPC@ZIF-90 stent was similar to natural aorta and ECs coverage on it was greatly strengthened after 30 days in a rat aorta vascular stent implantation model. Collectively, CoCr-Dopa/MIPC@ZIF-90 exhibited obvious superiority in reducing the formation of thrombus and promoting endothelial regeneration, which might meet the high requirement for the next generation of vascular stent.

Functional poly(e-caprolactone)/SerMA hybrid dressings with dimethyloxalylglycine-releasing property improve cutaneous wound healing

Medical dressings with multifunctional properties, including potent regeneration capability and good biocompatibility, are increasingly needed in clinical practice. In this study, we reported a novel hybrid wound dressing (PCL/SerMA/DMOG) that combines electrospun PCL membranes with DMOG-loaded methacrylated sericin (SerMA) hydrogel. In such a design, DMOG molecules are released from the hybrid dressing in a sustained mannerin vitro. A series ofin vitroassays demonstrated that DMOG-loaded hybrid dressing has multiple biological functions, including promotion of human umbilical vein endothelial cells proliferation and migration,in vitrovascularization, and the generation of intracellular NO. When applied to the cutaneous wound, the PCL/SerMA/DMOG dressing significantly accelerated wound closure and tissue regeneration by promoting angiogenesis in the wound area, collagen deposition, and cell proliferation within the wound bed. These results highlight the potential clinical application of PCL/SerMA/DMOG hybrid dressings as promising alternatives for accelerating wound healing via improved biocompatibility and angiogenesis amelioration.

Endothelial extracellular vesicles enhance vascular self-assembly in engineered human cardiac tissues.

The fabrication of complex and stable vasculature in engineered cardiac tissues represents a significant hurdle towards building physiologically relevant models of the heart. Here, we implemented a 3D model of cardiac vasculogenesis, incorporating endothelial cells (EC), stromal cells, and human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) in a fibrin hydrogel. The presence of CMs disrupted vessel formation in 3D tissues, resulting in the upregulation of endothelial activation markers and altered extracellular vesicle (EV) signaling in engineered tissues as determined by the proteomic analysis of culture supernatant. miRNA sequencing of CM- and EC-secreted EVs highlighted key EV-miRNAs that were postulated to play differing roles in cardiac vasculogenesis, including the let-7 family and miR-126-3p in EC-EVs. In the absence of CMs, the supplementation of CM-EVs to EC monolayers attenuated EC migration and proliferation and resulted in shorter and more discontinuous self-assembling vessels when applied to 3D vascular tissues. In contrast, supplementation of EC-EVs to the tissue culture media of 3D vascularized cardiac tissues mitigated some of the deleterious effects of CMs on vascular self-assembly, enhancing the average length and continuity of vessel tubes that formed in the presence of CMs. Direct transfection validated the effects of the key EC-EV miRNAs let-7b-5p and miR-126-3p in improving the maintenance of continuous vascular networks. EC-EV supplementation to biofabricated cardiac tissues and microfluidic devices resulted in tissue vascularization, illustrating the use of this approach in the engineering of enhanced, perfusable, microfluidic models of the myocardium.

Radial Egg White Hydrogel Releasing Extracellular Vesicles for Cell Fate Guidance and Accelerated Diabetic Skin Regeneration.

Topology and bioactive molecules are crucial for stimulating cellular and tissue functions. To regulate the chronic wound microenvironment, mono-assembly technology is employed to fabricate a radial egg white hydrogel loaded with lyophilized adipose tissue-extracellular vesicles (radial EWH@L-EVs). The radial architecture not only significantly modified the gene expression of functional cells, but also achieved directional and controlled release kinetics of L-EVs. Through the synergy of topographical and inherent bioactive cues, radial EWH@L-EVs effectively reduced intracellular oxidative stressand promoted the polarization of macrophages toward an anti-inflammatory phenotype during the inflammatory phase. Afterward, radial EWH@L-EVs facilitated the centripetal migration and proliferation of fibroblasts and endothelial cells as the wound transitioned to the proliferative phase. During the latter remodeling phase, radial EWH@L-EVs accelerated the regeneration of granulation tissue, angiogenesis, and collagen deposition, thereby promoting the reorganization chronic wound. Compared with the gold standard collagen scaffold, radial EWH@L-EVs actively accommodated the microenvironment via various functions throughout all stages of diabetic wound healing. This can be attributed to the orientation of topological structures and bioactive molecules, which should be considered of utmost importance in tissue engineering.

Targets and Mechanisms of Resveratrol against Endothelial-Mesenchymal Transition in Atherosclerosis: A Network Pharmacology Analysis Combined with In vivo Experiments

Background: Atherosclerosis (AS) is a chronic inflammatory disease characterized by plaque formation and endothelial dysfunction. Under pro-inflammatory conditions, the endothelial-mesenchymal transition (EndMT) plays an important role in the pathogenesis of AS. Resveratrol (RES) is a natural polyphenol in traditional Chinese medicines, which has been proven to possess anti-AS effects. However, the mechanism of RES treating AS through EndMT is not clear at present. Methods: RES targets were screened using databases such as SwissTargetPrediction and TargetNet, and AS and EndMT targets were searched using databases such as OMIM and DisGeNET. With the help of Venny 2.1, the key targets were selected by intersection. Next, the protein-protein interaction (PPI) network was constructed through the STRING 11.0 platform and Cytoscape software; gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotations were performed using DAVID. Further, Cytoscape was used to construct a drug-component-gene target-pathway network diagram to identify the core components and genes. Subsequently, an AS rat model was established. The blood lipid level of rats was detected by an automatic biochemical analyzer, and the expression level of the target protein was measured by western blotting. Results: Through network pharmacology analysis, 37 potential targets for RES treating AS and EndMT were identified, and the core targets for RES treating AS consisted of AKT1, TNF, MIMP9, and PPARG. GO enrichment analysis indicated that the treatment of AS with RES mainly involved the migration and proliferation of epithelial and endothelial cells. The KEGG pathway enrichment analysis revealed that the enrichment of TNF and Rap1 signaling pathways was most significant. Besides, RES effectively reduced the levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in the serum of AS rats, increased the level of high-density lipoprotein cholesterol (HDL-C), and significantly cut down the atherosclerosis index (AI). Twist1, calponin, α-SMA and VE-cadherin were considered as EndMT indexes. The results of the western blot demonstrated that the protein levels of Twist1, calponin and α-SMA were significantly decreased, while the protein expression level of VE-cadherin was notably increased in rats treated with RES. Moreover, RES could also reduce the expression levels of Rap1 and Epac1 proteins. Conclusion: RES is an effective anti-AS drug. Briefly, RES can effectively improve the blood lipid level of AS patients, regulate the expression of EndMT-related proteins, and alleviate the dysfunction of endothelial cells. Notably, the functions of RES are closely associated with the EPAC1-Rap1 pathway.

Poison Turned Panacea: Arsenic Trioxide Loaded Hydrogel for Inhibiting Scar Formation in Wound Healing.

Without intervention, the natural wound healing process can often result in scarring, which can have detrimental effects on both the physical and mental well-being of patients. Therefore, it is crucial to develop biomaterials that can promote healing without scarring. Regulating the Yes-associated protein-1/PDZ-binding motif (YAP/TAZ) signaling pathway is possible to reduce excessive fibrosis of fibroblasts and proliferation of vascular endothelial cells, ultimately impacting scar formation. Arsenic trioxide (ATO), an ancient drug with medicinal and toxic properties, has shown promise in regulating this pathway. An ATO-loaded hydrogel dressing (ATO@CS/SA) was created to facilitate scarless wound healing, utilizing chitosan (CS) and sodium alginate (SA) to prevent direct contact of ATO with the wound tissue and minimize potential side effects. In vitro studies demonstrated that low concentrations of ATO did not impact cell viability and even promoted proliferation and migration. Co-culturing the hydrogel with fibroblasts and vascular endothelial cells led to decreased expression levels of YAP and TAZ. Animal studies over a 90-day period revealed significant inhibition of scar formation with this system. Histological experiments further confirmed that the decreased expression of YAP and TAZ was responsible for this outcome. In conclusion, when administered at the appropriate dose, ATO can be repurposed from a traditional poison to a therapeutic agent, effectively suppressing excessive cell fibrosis and blood vessel proliferation and offering a novel approach to scar-free treatment.

3D-Cultured MC3T3-E1-Derived Exosomes Promote Endothelial Cell Biological Function under the Effect of LIPUS.

Porous Ti-6Al-4V scaffold materials can be used to heal massive bone defects because they can provide space for vascularisation and bone formation. During new bone tissue development, rapid vascular ingrowth into scaffold materials is very important. Osteoblast-derived exosomes are capable of facilitating angiogenesis-osteogenesis coupling. Low-intensity pulsed ultrasound (LIPUS) is a physical therapy modality widely utilised in the field of bone regeneration and has been proven to enhance the production and functionality of exosomes on two-dimensional surfaces. The impact of LIPUS on exosomes derived from osteoblasts cultured in three dimensions remains to be elucidated. In this study, exosomes produced by osteoblasts on porous Ti-6Al-4V scaffold materials under LIPUS and non-ultrasound stimulated conditions were co-cultured with endothelial cells. The findings indicated that the exosomes were consistently and stably taken up by the endothelial cells. Compared to the non-ultrasound group, the LIPUS group facilitated endothelial cell proliferation and angiogenesis. After 24 h of co-culture, the migration ability of endothelial cells in the LIPUS group was 17.30% higher relative to the non-ultrasound group. LIPUS may represent a potentially viable strategy to promote the efficacy of osteoblast-derived exosomes to enhance the angiogenesis of porous Ti-6Al-4V scaffold materials.

Heterogeneous porous hypoxia-mimicking scaffolds propel urethral reconstruction by promoting angiogenesis and regulating inflammation

The nasty urine microenvironment (UME) impedes neourethral regeneration by inhibiting angiogenesis and inducing an excessive inflammatory response. Cellular adaptation to hypoxia improves regeneration in numerous tissues. In this study, heterogeneous porous hypoxia-mimicking scaffolds were fabricated for urethral reconstruction via promoting angiogenesis and modulating the inflammatory response based on sustained release of dimethyloxalylglycine (DMOG) to promote HIF-1α stabilization. Such scaffolds exhibit a two-layered structure: a dense layer composed of electrospun poly (l-lactic acid) (PLLA) nanofibrous mats and a loose layer composed of a porous gelatin matrix incorporated with DMOG-loaded mesoporous silica nanoparticles (DMSNs) and coated with poly(glycerol sebacate) (PGS). The modification of PGS could significantly increase rupture elongation, making the composite scaffolds more suitable for urethral tissue regeneration. Additionally, sustained release of DMOG from the scaffold facilitates proliferation, migration, tube formation, and angiogenetic gene expression in human umbilical vein endothelial cells (HUVECs), as well as stimulates M2 macrophage polarization and its regulation of HUVECs migration and smooth muscle cell (SMCs) contractile phenotype. These effects were downstream of the stabilization of HIF-1α in HUVECs and macrophages under hypoxia-mimicking conditions. Furthermore, the scaffold achieved better urethral reconstruction in a rabbit urethral stricture model, including an unobstructed urethra with a larger urethral diameter, increased regeneration of urothelial cells, SMCs, and neovascularization. Our results indicate that heterogeneous porous hypoxia-mimicking scaffolds could promote urethral reconstruction via facilitating angiogenesis and modulating inflammatory response.

Androgen receptor activation inhibits endothelial cell migration in vitro and angiogenesis in vivo

Our previous research revealed that androgen receptor (AR) activation reduces endothelial cell proliferation via non-genomic pathways. We hypothesized that AR activation might also affect endothelial cell migration, a critical step in angiogenesis. Our data demonstrates that treatment of human umbilical vein endothelial cells (HUVECs) with AR agonists, metribolone (R1881) or dihydrotestosterone (DHT), results in a dose-dependent reduction in migration, which can be reversed by AR antagonists or AR knockdown. Mechanistically, R1881 inhibits HUVEC migration by suppressing RhoA activity through the cSrc/FAK/paxillin pathway and promoting RhoA degradation via RhoA-p27 complex formation, ultimately resulting in RhoA ubiquitination. Transfection with constitutively active RhoA-V14 rescues the inhibitory effect of R1881 on HUVEC migration. Furthermore, R1881 elevates intracellular vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) levels but reduces VEGF secretion from HUVECs. This reduction is attributed to the formation of VEGF-CTGF complexes in the cytosol induced by R1881. Transfection with RhoA-V14 reduces CTGF levels and VEGF-CTGF complex formation, leading to enhanced VEGF secretion. Pre-treatment with WP631, a CTGF inhibitor, mitigates the R1881-induced reduction in VEGF secretion and HUVECs migration. In vivo assessments using zebrafish angiogenesis and mouse matrigel plug assays validate the anti-angiogenic effects of R1881. These findings provide insight into the molecular mechanisms through which AR activation modulates endothelial cell migration and angiogenesis.

Bioactive Nb2C MXene-Functionalized Hydrogel with Microenvironment Remodeling and Enhanced Neurogenesis to Promote Skeletal Muscle Regeneration and Functional Restoration.

The complete structure-functional repair of volumetric muscle loss (VML) remains a giant challenge and biomedical hydrogels to remodel microenvironment and enhance neurogenesis have appeared to be a promising direction. However, the current hydrogels for VML repair hardly achieve these two goals simultaneously due to their insufficient functionality and the challenge in high-cost of bioactive factors. In this study, a facile strategy using Nb2C MXene-functionalized hydrogel (OPTN) as a bioactive scaffold is proposed to promote VML repair with skeletal muscle regeneration and functional restoration. In vitro experiments show that OPTN scaffold can effectively scavenge reactive oxygen species (ROS), guide macrophages polarization toward M2 phenotype, and resist bacterial infection, providing a favorable microenvironment for myoblasts proliferation as well as the endothelial cells proliferation, migration, and tube formation. More importantly, OPTN scaffold with electroactive feature remarkably boosts myoblasts differentiation and mesenchymal stem cells neural differentiation. Animal experiments further confirm that OPTN scaffold can achieve a prominent structure-functional VML repair by attenuating ROS levels, alleviating inflammation, reducing fibrosis, and facilitating angiogenesis, newborn myotube formation, and neurogenesis. Collectively, this study provides a highly promising and effective strategy for the structure-functional VML repair through designing bioactive multifunctional hydrogel with microenvironment remodeling and enhanced neurogenesis.

CD26 Is Differentially Expressed throughout the Life Cycle of Infantile Hemangiomas and Characterizes the Proliferative Phase.

Infantile hemangiomas (IHs) are benign vascular neoplasms of childhood (prevalence 5-10%) due to the abnormal proliferation of endothelial cells. IHs are characterized by a peculiar natural life cycle enclosing three phases: proliferative (≤12 months), involuting (≥13 months), and involuted (up to 4-7 years). The mechanisms underlying this neoplastic disease still remain uncovered. Twenty-seven IH tissue specimens (15 proliferative and 12 involuting) were subjected to hematoxylin and eosin staining and a panel of diagnostic markers by immunohistochemistry. WT1, nestin, CD133, and CD26 were also analyzed. Moreover, CD31pos/CD26pos proliferative hemangioma-derived endothelial cells (Hem-ECs) were freshly isolated, exposed to vildagliptin (a DPP-IV/CD26 inhibitor), and tested for cell survival and proliferation by MTT assay, FACS analysis, and Western blot assay. All IHs displayed positive CD31, GLUT1, WT1, and nestin immunostaining but were negative for D2-40. Increased endothelial cell proliferation in IH samples was documented by ki67 labeling. All endothelia of proliferative IHs were positive for CD26 (100%), while only 10 expressed CD133 (66.6%). Surprisingly, seven involuting IH samples (58.3%) exhibited coexisting proliferative and involuting aspects in the same hemangiomatous lesion. Importantly, proliferative areas were characterized by CD26 immunolabeling, at variance from involuting sites that were always CD26 negative. Finally, in vitro DPP-IV pharmacological inhibition by vildagliptin significantly reduced Hem-ECs proliferation through the modulation of ki67 and induced cell cycle arrest associated with the upregulation of p21 protein expression. Taken together, our findings suggest that CD26 might represent a reliable biomarker to detect proliferative sites and unveil non-regressive IHs after a 12-month life cycle.